Gaseous electric discharge lamp device



Feb. 11, 1936. K. WIEGAND GASEOUS ELECTRIC DISCHARGE LAMP DEVICE Filed June 7, 1955 INVENTOR {Km L 99 ATT RNEY Patented Feb. 11, 1936 UNITED STATES PATENT OFFICE Kurt Wiegand, Berlin-Neu-Tempelhof Germany I assignor to General Electric Company, a cor poration of New York Application June 7, 1935, Serial No. 25,495

Germany June 15, 1934 2 Claims.

The present invention relates to gaseous electric discharge lamp devices generally and more particularly the invention relates to such devices having a quantity of metal therein the vapor of. which is light emitting during the operation of the device.

In the manufacture of such devices care must be exercised in-introducing the vaporizable metal into the envelope of the lamp that the metal remain free from deleterious impurities which would have a harmful effect upon the efllciency, the operating characteristics and the light emission of such devices. This can be accomplished by enclosing the pure metal in a sealed container which is introduced into the lamp envelope during the manufacture of the lamp and which container is ruptured to permit the escape of the vaporizable material therefrom into the lamp envelope after the lamp is otherwise completed.

The object of the present invention is to provide an improved method of and means for intro ducing vaporizable material into the container of a gaseous electric discharge lamp device. Another object of the invention is to simplify the manufacture of gaseous electric discharge lamps the gaseous atmosphere of which consists of or comprises a metal vapor. A further object of the invention is to provide means for introducing a quantity of vaporizable material into the envelope of a gaseous electric discharge lamp which means serves a useful purpose throughout the life of the lamp device. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description.

The above objects of the invention are attainedby utilizing as the container for the vaporizable metal to be introduced into the lamp envelope an elongated tube of sufficient length to extend along the discharge path between the electrodes sealed into the lamp envelope and terminate adjacent said electrodes. The elongated tube is made of conducting material or. surrounds an element of such material and facilitates the starting of the gaseous electric discharge in the lamp. The tube thus serves a useful purpose during the life of the lamp and the manufacturing cost of the lamp is reduced.

The invention will be readily understood from an inspection of the drawing accompanying and forming part of this specification and from a perusal of the following detailed description thereof.

In the drawing.

Fig. 1 is a side elevational, partly sectional view of one embodiment of the invention, and

Fig. 2 is a similar view of another embodiment of the invention.

Like numbers denote like parts in both the fig- 5 ures. 1

Referring to Fig. 1 of the drawing the lamp comprises an elongated, tubular envelope I having electrodes 2 sealed therein and a gaseous atmosphere therein, such as argon, neon or nitrogen, or a mixture of such gases. Each of said electrodes 2 consists of a heater filament, such as a tungsten or a nickel filament, wrapped around a curved, compacted body of electron emitting material, such as. barium or strontium oxide or a mixture thereof. Each of said electrodes 2 is mounted on a pair of current leads sealed into said envelope I, the heating filament is connected to the inner ends of said leads. Said electrodes 2 are heated to an electron emitting temperature during the starting period of the lamp by a heater current applied thereto.

A tube 3 of insulating material is supported in said envelope I by a pair of spring clips 8 wrapp d around said tube 3 adjacent the ends thereof and pressing against the inner surface of said envelope I. The tube 3 extends along the discharge path between said electrodes 2 and terminates a short distance from the electrodes 2.

A helical resistance wire 4 is surrounded by said tube 3. Said resistance 4 has two straight end pieces 5 which project beyond the end of said tube 3. Before being introduced into the envelope I the tube 3 is filled with the vaporizable material, such as sodium, caesium, rubidium, or zinc, and is closed by covering the open ends thereof with a low melting point material 1 such as parafln, wax or boric oxide. The tube 3 is then inserted in said envelope I through one end thereof after which the other steps in the manufacture of the lamp are carried out. When the envelope I has been sealed and the lamp is otherwise complete the material I is heated to the melting temperature thereof, as by operating the lamp, which opens the ends of said tube 3 to permit the vaporizable material i to enter the envelope I. The wire 5, l facilitates the starting of the device in the manner well known in the art.

The embodiment of the invention illustrated in Fig. 2 of drawing is similar in all respects to that shown in Fig. 1 except that in this embodiment each of the electrodes II are mounted on a single current lead and are heated to an electron emitting temperamre by the voltage drop thereat and the discharge current flow therethrough. The tube 3 consists of metal and .facilitates the starting of the gaseous electric discharge between said electrodes in the same manner as the elements 4 and 5 of the embodiment of Fig. 1. In this embodiment the ends or the tube 6 are closed by plugs 9 of low melting point material.

In the manufacture of both embodiments of the invention the tube 3 is first filled with the desired vaporizable material, preferably sodium, and the ends thereof are then closed by bodies of low melting point material. The closed tube 3 is then inserted in the container I after which the electrodes 2 or I0 are sealed therein and the other steps of manufacture of the lamp, such as exhaustion thereoi. and introduction of the starting gas therein, such as a mixture or argon and neon, are then carried out. When the lamp is otherwise completed suflicient heat is applied to the entire tube 3, or at least to the ends thereof, to raise the caps I or the plugs 9 to the melting temperature thereof. The vaporizable material 6 in the tube 3 is then free to distill or otherwise travel into the container I from the tube 3.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention. it will be understood that various omissions, substitutions and changes in theiorms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention.

What we claim as new anddesire to secure by Letters Patent 0! the United States, is:-

1. A gaseous electric discharge device comprising an envelope, electrodes sealed therein, a gaseous atmosphere therein, an elongated tube in said envelope, said tube comprising an element of conducting material extending along the discharge path between said electrodes and terminating adjacent said electrodes and a quantity of vaporizable material in said tube.

2. A gaseous electric discharge device comprising an envelope, electrodes sealed therein a gaseous atmosphere therein, an elongated tube in said envelope, said tube comprising an element of conducting material extending along the discharge path between said electrodes and terminating adjacent said electrodes and a quantity or vaporizable material in said tube, the ends of said tube being closed by bodies of low melting point material.

KURT WIEGAND. 

